peteg's blog

Screwing up my nerve

/hacking/nixie_clock | Link

I wired up most of the first nixie tube to the board today. It's a bit hairy for a few reasons: a misconnection could fry me or the ARM board, and small mistakes could lead to extensive resoldering. Thus far things have gone OK; it turns out my 33kΩ-series/33kΩ-pull-down setup is strong enough while the ARM board is unpowered, but once the ARM board is fired up the 100kΩ pull-up on the ts7260 is enough to fire the anode switcher. I cured this empirically, by reducing the series to 11kΩ and the pull-down to 4.7kΩ. It works, and the voltage levels seem plausible, but they still imply the current is very weak. I wonder about noise.

Now I can switch amongst the cathodes (those I've wired up) using the K155ИД1, and that's about that. I need to replace all my resistor pairs and solder up a further three tubes. Joy.

In other news John Taylor's high-voltage power supply turned up. Took about four days to get here from California. I haven't fired it up yet, but will after I get the display board completed.

The Narrow Margin

/noise/movies | Link

Another noir from the early 1950s. I have no idea why I picked this one in particular; perhaps because one of the actresses is also in Kubrick's The Killing. The acting is a bit patchy, the plot a bit predictable, modulo a twist of a very short duration.